Duel Wielding is a skill to attack with two weapons. It is basically a Penalty Combat Skill Level with a special feature. You can now use the maneuver: 2 WPN Strike without the -2 OCV Penalty. Additionally, the character no longer suffers from the -3 Off-Hand penalty for attacks made using the off hand.
If a second level is purchased for (4 points) the character offsets 3 of the DCV penalty.